This invention relates to toothpaste compositions with which plastics containers having oxygen permeability of 3 cc/m.sup.2 .multidot.day.multidot.atm or more are filled. More particularly, this invention relates to toothpaste compositions which exhibit increased antiseptic properties when received in plastics containers including plastics tubes, aluminum foil-plastics coating laminate tubes and plastics bottles.
In general, toothpaste compositions are contained in suitable containers and squeezed out of the containers onto a toothbrush immediately before they are used. It is therefore required that such toothpaste is kept hygienically acceptable in the container, easily extruded through a container opening, easily applied onto a tooth brush, and retains its shape on the toothbrush.
Commonly used toothpaste containers are generally classified into two groups: metal containers including aluminium tubes and plastic containers including plastics tubes formed solely of plastics material, laminate tubes comprising an aluminium foil coated with a plastics layer on an inner or each surface and formed into a tube, and plastic bottles. Such a plastics bottle has a wall of substantial thickness and can restore its shape immediately after the pressure applied to squeeze a desired amount of toothpaste out of the bottle is released. The plastics bottle has an aesthetic appearance and can stand on its cap, requiring a minimum space.
Among these containers, as a result of the interaction of a container with its contents or toothpaste composition, metal containers, especially aluminum tubes are susceptible to corrosion or pitting. This problem may be overcome by modifying the formulation of toothpaste compositions or by replacing aluminum tubes by plastics containers.
Concerning plastics containers, no substantial problem has heretofore been found when toothpaste compositions are received in plastics containers including plastic tubes, plastics bottles, and laminate tubes comprising an aluminum foil coated with a plastics layer on an inner or each surface. However, the inventors have experimentally discovered that if contaminants are accidentally introduced into a toothpaste container from the environment, plastics containers capable of more or less restoring their shape immediately after the pressure applied to squeeze a desired amount of toothpaste out of the container is released allow aerobic bacteria to grow or propagate easily in their contents or toothpaste as compared with aluminum tubes. Particularly when plastics containers having oxygen permeability of 3 cc/m.sup.2 .multidot.day.multidot.atm or more are filled with toothpaste compositions, aerobic bacteria would grow or propagate very easily. Although aerobic bacteria are not pathogenic, the presence of such bacteria in a substantial quantity would have undesired influence on the flavor and stability of toothpaste compositions. It has been thus found that toothpaste compositions should be more antiseptic when plastic containers, particularly those containers with a high restoring force are used.
In general, conventional toothpastes are rendered antiseptic by incorporating antiseptics and bactericides therein. However, some bactericides, for example, quarternary ammonium salt bactericides have been reported as coloring tooth enamel. In addition, the use of such antiseptics and bactericides is strictly limited by Governmental regulations. Since toothpaste compositions are destined for oral application, it is desired for increased hygienic safety that the amount of antiseptics and bactericides blended is as small as possible.